I am trying to print bellows out of TPU 95A HF. No matter what I keep getting issues in the overhang areas.
The model is .8mm wall thickness. Filament has been dried for 18 hours in AMS HT and is being printed from AMS HT bypass while also heating the box to 55c to prevent any moisture uptake.
I have done several test prints and the most recent are better, however i keep getting issue with drooping, sagging, and holes near corners at the overhangs.
So far I’ve tried turning down the AUX and part cooling fans. They were blowing with so much force it was causing the TPU filament to fly off the model as it was being laid down. Reducing fans helped but still getting holes.
It always appears that when the bellows overhang is inwards (to center of built plate) it performs worse than outward overhangs (pointing away from buildplate center)
Added images of the model, actual prints, and print settings.
Anyone have any suggestions?
I don’t think it would ever work. This model is supposed to be printed in Vase mode. You should try to visualize how the toolpath lays down themselves. And you should check the slicing results. For me, by the way it looks, I’m pretty sure you can tell the issues if you actually check the slicing results. Post the 3mf file if you need some assistance so that next time you can check it yourself.
The creator says vase and regular mode work fine in his documentation. They specifically states it works with .4, .6, and .8 nozzle either with standard two walls or in vase mode print. I even tried pushing a 0.8 line width on a .4 nozzle at 0.1 layer height in vase mode and no dice.
Overall vase mode fares worse.
Slicing looks normal as expected and on other filament print just fine as overhangs are less than 45 degrees.
Here is attached Bambu Studio project file:
Edit: Uploaded wrong file. See proper file two posts below.
Something I would try is .5mm outer wall and .42 inner wall, to give the outer line a better anchor. Besides that, you could use pla as support.(just dont do 0 support to part gap like if you were using actual support material, because they will permanently bond)
No… Too low layer height would be very hard to print for challenging materials.
Also could you please upload the 3mf file that you have processed with Bambu Studio (and saved in Bambu Studio)? The one you shared could be generated from Orca or Prusa so it’s not showing slicing settings and slicing results correctly in Bambu.
Looks like i uploaded the wrong one.
TPU Bellows Test 03.3mf (34.8 KB)
RE: .1 layer height
Others on printables have claimed it prints on their well tuned Prusas at that layer height.
Change to Arachane wall generator to remove those gap infills and see if it helps. also your seam placement is not good, because you enabled scarf seam for something it’s not meant for.
Scarf Seam, Gap Infill, both are very challenging for extrusion control. Especially for scarf seam. I would never use it on TPU unless it’s a round vase…
I’ll give Arachne a try.
I’ve tried with and without scarf seams. Both failed about the same though before. I’ll try Arachne and without scarf again to test along with streetsports idea about 0.5 outer wall.
